Barley

Barley is the fourth most important grain crop in the United States.
Acreage planted in 1966 and 1967 averaged about 10.6 million, with an
average yield for the two years of 381.7 million bushels.

Barley is one
of the most ancient of cultivated grains. Grains found in pits and
pyramids in Egypt indicate that barley was cultivated there more than 5000
years ago. The most ancient glyph or pictograph found for barley is dated
about 3000 B.C. Numerous references to barley and beer are found in the
earliest Egyptian and Sumerian writings.

The origin of barley is still not known. There are differing views among
researchers as to whether the original wild forms were indigenous to
Eastern Asia, particulariy Tibet, or to the Near East or Eastern
Mediterranean Area, or both. Possibly in a crop so long cultivated this
can never be resolved with certainty. J. R. Harlan, in U.S.D.A.
Handbook 338, Barley: Origin, Botany, Culture, Winterhardiness, Genetics,
Utilization, Pests, summarizes the evidence for different viewpoints.

Species and Characteristics of Barley

Three species of Hordeum
constitute the barleys under cultivation.

They are derived species, not
known as such in nature. All have 14 cbromosomes in the diploid stage and
inter-cross readily. They are characterized as follows:

Hordeum vulgare L. These are 6-rowed barleys with a tough rachis or spike
stem. All florets are fertile and develop normal kernels. Within the
species are two groups: (1) The typical group in which lateral kernels are
only slightly smaller than the central one. (2) The intermediate group in
which lateral kernels are distinctly smaller than central ones. This group
may contain kinds with sterile or near sterile lateral spikelets. The two
groups may overlap and are not fully distinct.

Hordeum distichon L. This species is the 2-rowed barleys with a tough
rachis. The central spikelets all contain a fertile flower, while flowers
in the lateral spikelets are either male or sexless. Two groups of
varieties occur: (1) The typical 2-row group, with lateral flowers
containing lemma, palea and reduced sexual parts. (2) The deficiens group,
with lateral flowers containing no sexual parts.

Hordeum irregulare E. Aberg and Wiebe. This is an irregular barley with a
tough rachis, but with lateral flowers reduced in some instances to a stem
piece only; and others fertile, sterile or sexless. Central spikelets
contain fertile flowers and set seeds.

A number of species of Hordeum are native in various parts of the world.
Hitchcock (Manual of Grasses of the United States, Ed. 2, U.S.D.A. Misc.
Pub. 200, 1951) lists 11 species of barley grasses as occurring in the
United States. None of the native species is in cultivation.

Barley plants are annual grasses which may be either winter annuals or
spring annuals. Winter annuals require a period of exposure to cold in
order to produce flowers and set seeds, thus are planted in the fall. They
form a rosette type of growth in fall and winter, developing elongated
stems and flower heads in early summer. If seeded in the spring they fail
to produce seed heads. Winter varieties form branch stems or tillers at
the base so several stems rise from a single plant. The winter varieties
of barlev are more hardy than winter oats, but somewhat less hardy than
winter wheat. Around a fourth of the barley grown in the United States is
of winter varieties. Spring varieties do not require exposure to cold in
order to devlop seed heads. Also, they do not have a typical rosette stage
and so develop fewer tillers than winter varieties. They are the only kind
adapted to areas with very cold winters. For best production they should
be seeded as early as land can be worked in the spring.

The stems of both winter and spring varieties may vary in length from 1 to
4 feet, depending on variety and growing conditions. Stems are round,
hollow between nodes, and develop 5 to 7 nodes below the head. At each
node a clasping leaf develops. In most varieties the leaves are coated
with a waxy chalklike deposit. The density of this varies, and in some
varieties no waxiness is present and leaves are glossy. Shape and size of
leaves varies with varietv, growing conditions, and position on the plant.

The spike, which contains the flowers and later the mature seeds, consists
of spikelets attached to the central stem or rachis. Stem intervals
between spikelets are 2 mm. or less in dense headed varieties and up to 4
to 5 mm. in lax or open headed kinds. Three spikelets develop at each
node on the rachis. Barley varieties are classed as 2-row or 6-row. In
2-row varieties only the central spikelet develops a fertile flower and
seed. In 6-row varieties all three of the spikelets at each node develop a
seed.

Each spikelet has two glumes rising from near the base. These are linear
to lanceolate and flat and terminate in an awn. The glumes minus the awn
are about half the length of the kernel in most varieties, but this varies
from less than half to equal to the kernel in length. Glumes may be
covered with hairs, weakly haired or hairless. The awns on the glumes may
be shorter than the giume, equal in length or longer. The glumes are
removed in threshing.

The barley kernel consists of the caryopsis, or internal seed, the lemma
and palea. In most barley varieties the lema and palea adhere to the
caryopsis and are a part of the grain following threshing. However, naked
or hutless varieties also occur. In these the caryopsis is free of the
lemma and palea and threshes out free as in wheat. This type is grown
mainly where barley is used for human food and is rarely found in the
United States.

The lemmas in barley are usually awned. Awns vary from very short up to as
much as 12 inches in length. Edges of awns may be rough or "barbed"
(bearded) or nearly smooth. Awnless varieties are also known. In 6-row
barley awns are usually more developed on the central spikelets than on the
lateral ones.

The barley kernel is generally spindle shaped. In commercial varieties
grown in the United States length ranges from 7 to 12 mm. Kernels from
2-rowed varieties are symmetrical. In 6-rowed varieties the third of the
kernels from the central spikelets are symmetrical, but the two-thirds from
lateral spikelets are twisted. The twist is most apparent at the
attachment end, less conspicuous at the terminal. The dorsal surface of
kernels is smooth, the ventral surface grooved.

The period from
flowering until barley is ready for harvest may vary from 40 days to as
long as 55 days, varying with varieties and climatic conditions.

Cultivated Variety Groups

Some 150 varieties of barley are cultivated in the United States, many
on a minor scale. Varieties are constantly changing as new ones are devloped
and tested while others pass out of cultivation. These varieties fall into four
general groups, as follows:

Manchuria - OAC 21 - Aderbrucker Group- These are 6-rowed, awned,
spring-type varieties with medium sized kernels. The type is believed to have
come originally from Manchuria. Plants are tall with open or lax, nodding
heads. They tend to shatter badly in dry climates. These are grown mainly in
the upper Mississippi Valley and are extensively used for malting.

Coast Group. These varieties trace to North African ancestry and are
grown in California and Arizona, also in the Inter-Mountain Region. They are
6-rowed, awned, with large kernels, and short to medium length stems. Spikes
are medium to short, dense and generally held erect to semierect. They mature
early and are not prone to shatter. They have a spring growth habit but may be
fall or winter seeded in California and Arizona where winters are mild.

Tennessee Winter Group. Varieties of this group trace to the
Balkan-Caucasus Region or Korea. They are 6-rowed, avrned, with mid-long lax
spikes which tend to nod. Plants are medium tall, of winter habit. These
varieties are fall seeded and are grown in the southeastern quarter of the
United States.

Two-rowed Group. This group includes types tracing to Europe and Turkey--the Turkish type being adapted to areas with marginal rainfall. Varieties in
this group are grown principally in the Pacific and InterMountain States and to
some extent in the Northern Great Plains. Varieties are mainly spring type
though 2-rowed winter varieties are known. Some varieties are used mainly for
malting, others for feed.

Uses of Barley

Half or more of the barley grown in the United States is used for
livestock feed. As feed it is nearly equal in nutritive value to kernel corn.
It is especially valuable as hog feed, giving desirable portions of firm fat
and lean meat. The entire kernel is used in feed, generally after grinding or
steam rolling. Malt sprouts from malting as well as brewers grain--byproducts
of brewing--are also valuable livestock feeds.

Around 25 percent of the barley crop is used for malting in the United States.
Of the malted barley some 80 percent is used for beer, around 14 percent for
distilled alcohol products, and 6 percent for malt syrup, malted milk and
breakfast foods. For malting, the barley is steeped in aerated water in large
tanks for 45 to 65 hours, then transferred to germinating tanks or compartments
where it is held with intermittent stirring for 5 to 7 days at temperatures of
60-70°F. During this treatment root sprouts emerge, but not the stems. This
"green" malt is then dried in hot air kilns. For making beer the dried malt is
crushed between rollers, mixed in proper proportions with slightly warm water,
and held under rigidly controlled temperatures. The starch is converted by
enzymatic reaction into maltose and dextrins. Proteins are also broken down by
enzyme action. Upon completion of this process the solids settle out, the
extract is filtered, then boiled with hops to add flavor, then cooled. Yeast is
added to ferment the sugars into alcohol and carbon dioxide. The hop residue
and proteins are then removed and the product (beer) is aged, chilled,
filtered, pasteurized and bottled. Keg beer is similar but is not pasteurized
or bottled. The solids from this process (brewer's grain) are a valuable
livestock feed.

Barley for human food is made into pearl barley by using abrasive disks to
grind the hulls and bran off the kernels. Alter three successive "Pearlings" or
grinding operations all the bull and most of the bran is removed. At this stage
the remaining kernel part is known as pot barley. Two or three additional
pearlings produce pearl barley, in which most of the embryo is removed. These
later pearlings also produce barley flour. Pot and pearl barley are used in
soups and dressings. The flour is used in baby foods and breakfast cereals, or
mixed with wheat flour in baking.

Barley is also grown as a hay crop in some areas. For hay, only smooth-awned
varieties or awnless are used. Winter barley also may be pastured moderately
before the stems start to elongate. It furnishes nutritive pasturage, and grain
yields are not seriously reduced.